Visualizing myocardial inflammation in a rat model of type 4 cardiorenal syndrome by dual-modality molecular imaging

Type 4 cardiorenal syndrome (CRS) is a life-threatening world health problem in which chronic kidney disease leads to progressive cardiovascular disease. In type 4 CRS, cardiac inflammation is an excellent target for both detection and therapy; however, this progression was underestimated by previous studies due to the lack of effective detection methods. To noninvasively visualize cardiac inflammation and monitor therapeutic efficacy of anti-inflammatory treatment in type 4 CRS, we here synthesized a dual-modality magneto-fluorescent nanoparticle (MNP) by combining ultrasmall superparamagnetic iron oxide nanoparticle and Rhodamine B for both magnetic resonance imaging (MRI) and optical imaging. This dual-functional MNP exhibited excellent performance such as high r2 relaxivity coefficient (283.4 mM⁻¹ s⁻¹), high magnetism (96.7 emu/g iron) and a near neutral surface charge to minimize the reticuloendothelial system uptake. In vivo cardiac MRI showed significant negative contrast in the type 4 CRS rats, and the signal intensity on optical imaging was significantly higher in the type 4 CRS group compared with sham-operated and drug-treated groups. The specific targeting profile of MNPs to monocyte-macrophages was proven by histopathological analysis. Taken together, we demonstrate that this dual-modality strategy is feasible for noninvasively assessing myocardial inflammation and monitoring therapeutic efficacy in type 4 CRS.     

老年患者术后认知功能障碍的多模态MRI研究进展

老年人术后认知功能障碍(postoperative cognitive dysfunction,POCD)严重地影响老年人的健康和生活,造成家庭和社会的严重负担,正日益受到人们的重视。近年来,脑MRI在检测老年人POCD中的脑结构、功能及代谢变化以及探讨其发病的神经机制方面的研究日益增多。结合多模态磁共振成像技术,能同时从细微结构、功能及代谢层面对疾病进行研究,为POCD的发病机制提供新的见解,为早期诊断治疗提供新的思路。     

Self-assembled magnetic fluorescent polymeric micelles for magnetic resonance and optical imaging

Stable and cytocompatible hybrid PEGylated micelles with multimodal imaging capabilities are described. The F₃O₄-encapsulated polymeric micelles composed of cores containing magnetic nanoparticles and polyethylene glycol (PEG) shells are synthesized by self-assembly of amphiphilic poly(HFMA-co-VBK)-g-PEG copolymers and oleic acid stabilized Fe₃O₄ nanoparticles. The Fe₃O₄ magnetic nanoparticles in the core produce T₂-weighted MR imaging functionalities, whereas the small fluorescent monomer carbazole in the polymer shell introduces good fluorescent properties. The multifunctional micelles exhibit excellent paramagnetic properties with the maximum saturation magnetization of 9.61 emu/g and transverse relaxivity rate of 157.44 mm⁻¹ S⁻¹. In vivo magnetic resonance imaging (MRI) studies reveal enhanced contrast between the liver and spleen. Fluorescence spectra show characteristic emission peaks from carbazole at 350 nm and 365 nm and vivid blue fluorescence can be observed by 2-photon confocal scanning laser microscopy (CLSM). In vivo optical imaging demonstrates the unique fluorescent characteristics of the Fe₃O₄-encapsulated polymeric micelles in the liver and spleen and the excellent multifunctional properties suggest potential clinical use as nanocarriers in magnetic resonance imaging and optical imaging.     

Multi-modal transfection agent based on monodisperse magnetic nanoparticles for stem cell gene delivery and tracking

Directing the controlled differentiation and tracking of stem cells is essential to achieve successful stem cell therapy. In this work, we describe a multi-modal (MR/optical) transfection agent (MTA) for efficient gene delivery and cell tracking of human mesenchymal stem cells (hMSCs). The MTA was synthesized through a facile two-step approach with 1) ligand exchange of a catechol-functionalized polypeptide (CFP) and 2) chemical immobilization of fluorescence labelled cationic polymer via aminolysis reaction. Cationic polymer-immobilized MTAs with size of ∼40 nm exhibit greatly enhanced colloidal stability in aqueous solution. In addition, the MTAs were capable of binding DNA molecules for transfection. The MTA/pDNA complex showed relatively good transfection efficiency in hMSCs (compared to the commercial transfection agent, Lipofectamine) and good biocompatibility. MTA-treated hMSCs were successfully visualized after transplantation via MR and optical imaging system over 14 days. These studies highlight the challenges associated with the potential advantages of designing multi-modal nanostructured materials as tools for genetic materials delivery and cell-tracking in stem cell therapy.     

体素内不相干运动弥散加权成像在受压腰骶神经根诊断中的应用

目的 探讨MR体素内不相干运动(IVIM)弥散加权成像(DWI)在受压腰骶神经根诊断中应用的可行性。方法 前瞻性对照研究。纳入2017年4—10月30例腰椎间盘突出致神经根受压患者(观察组)的常规腰椎MR序列及3D-Fiesta序列、IVIM-DWI序列图像;另按性别、年龄匹配纳入30名健康志愿者作为对照组。在GE ADW 4.6工作站,使用MADC软件包测量对照组双侧L₄、L₅、S₁神经节的扩散系数(D)、灌注相关扩散系数(D*)、灌注分数(f)和表观扩散系数(ADC)值,以及观察组患者受压侧及其对侧神经根的D、D*、f、ADC值。比较对照组同节段左右两侧神经节和不同节段神经节各观察项目测量值,以及观察组受压侧神经根与对侧正常神经根各观察项目测量值。绘制受压神经根D值和ADC值的ROC曲线,评价诊断效果。结果 对照组L₄、L₅、S₁神经根的D值分别为(0.603±0.064)×10^-3 mm²/s、(0.624±0.079)×10^-3 mm²/s、(0.628±0.088) ×10^-3 mm²/s, D*值分别为(3.815±0.541) ×10^-3 mm²/s、(3.862±0.414)×10^-3 mm²/s、(3.915±0.611) ×10^-3 mm²/s; f值分别为0.454%±0.076%、0.484%±0.101%、0.445%±0.094%; ADC值分别为(0.934±0.085)×10^-3 mm²/s、(0.945±0.051)×10^-3 mm²/s、(0.953±0.064)×10^-3 mm²/s。观察组神经根受压侧D、D*、f、ADC值分别为(0.669±0.081)×10^-3 mm²/s、(3.852±0.776)×10^-3 mm²/s、0.528%±0.115%、(1.096±0.087)×10^-3 mm²/s,健侧D、D*、f、ADC值分别为(0.617±0.080)×10^-3 mm²/s、(3.961±0.684)×10^-3 mm²/s、0.479%±0.083%、(0.938±0.074)×10^-3 mm²/s。对照组同节段左右两侧神经节和不同节段神经节所测D、D*、f、ADC值,差异均无统计学意义(P值均＞0.05)。观察组受压侧神经根与对侧正常神经根比较:D和ADC值均升高,差异均有统计学意义(P值均＜0.01);D*、f值差异均无统计学意义(P值均＞0.05)。绘制并分析ROC曲线,D值对诊断神经根受压具有较高效能,其次是ADC值,D值的AUC为0.923(95%CI 0.803~0.987),ADC值的 AUC为0.895(95%CI 0.865~0.999)。结论 IVIM模型的MR DWI技术可用于腰骶神经根检查,且与单指数模型的MR DWI相比能更详细、准确地反映神经根受压后的病理改变。     

骶前区血管网磁共振成像动态增强扫描不同对比剂剂量成像效果的比较

目的探讨不同剂量对比剂磁共振成像（MRI）动态增强扫描对骶前区血管网三维成像的效果,并评价减少对比剂用量的可行性及临床应用价值。方法选取2012年2月至5月间于本院就诊的40例因盆腔良性病变常规行MRI检查的成年女性患者,数字随机法随机分为两组,A组对比剂剂量为钆浓度0．5mol,L20ml,B组为40ml。采用ACHIEVA3．0TX双源磁共振扫描仪对患者行盆腔e-THRIVE3D等体素动态增强MRI序列扫描,采用最大密度投影（MIP）及容积再现重组（VR）后处理技术进行骶前区血管网重建成像,观察骶前区血管的正常解剖及走行,计算骶正中动脉、骶前区横干静脉显示率和骶正中动脉横径。以骶正中动脉为靶点,分别对两组MIP图像质量采取5分制主观评价方法,通过测定信号强度（SI）、信噪比（SNR）和对比噪声比（CNR）的客观评价指标进行综合比较。结果两组患者图像中骶正中动脉均显示清晰,成功率为100％;骶前区横干静脉的总显示率为72．5％（29／40）,其中A组显示率为75％（15／20）,B组显示率为70％（14／20）,差异无统计学意义。在e-THRIVE序列横断位图像上A组骶正中动脉横径与B组差异无统计学意义[（1．42±0．06）mm比（1．38±0．07）mm,P=0．117]。A组骶正中动脉MIP图像质量主观评价评分略低于B组,但差异无统计学意义[（2．95±0．69）分比（3．10±0．66）分,P=0．479]。A组骶正中动脉MIP图像质量客观评价SI、SNR与B组差异无统计学意义（SI：719．63±124．91比811．66±170．60,SNR：61．71±17．35比74．97±27．91,均P〉0．05）,而CNR低于B组（45．68±13．35比62．41±23．37,P〈0．05）。结论采用体素动态增强成像序列扫描及后处理技术可以清晰显示骶前区血管网。0．5mol/L20ml钆双胺的剂量同样能达到双倍剂量的显像效果,均可显示骶正中动脉及横干静脉的形?     

核磁共振弥散峰度成像在脑中风诊断中的应用

目的 研究弥散峰度成像(DKI)对脑组织灰质和白质的描述以及在脑中风诊断中的应用.方法 采用2例正常人以及15例脑中风患者(包含9例脑梗死,急性、亚急性和陈旧性各占3例)的脑部核磁共振图像作为试验数据.针对每例数据各个像素位置,分别对9个不同弥散梯度场下各个信号强度进行非线性拟合得到弥散系数(D值)和弥散峰度(K值),进而做出ADC图和DKI图.观察比较分析各例在ADC图和DKI图的表现.结果 DKI成像具有更多的纹理细节,包含更丰富的组织特征.急性、亚急性脑梗死病灶在DKI图呈现高信号,陈旧性脑梗死病灶在DKI图呈现低信号,平均峰度相对值(rMK)分别为2.193±0.166,1.789±0.162,0.564±0.069.结论 DKI对脑组织尤其是灰质以及一些脑中风病灶的描述相对于ADC图包含更多的组织信息.脑梗死病灶的rMK值具有特征性演变规律.     

Two applications of wavelets and related techniques in medical imaging

We present two applications of wavelet and related techniques to problems arising in medical imaging. Both make considerable use of the edge detection and classification properties of wavelet-type representations. First we describe simple and effective techniques for image denoising and contrast enhancement based on the multiscale edge representation of images. These techniques are sufficiently flexible to successfully address the varying requirements posed by several different medical imaging modalities in common use today. Experimental results are presented to illustrate the application of these techniques to various types of medical images. Next we describe adapted waveform encoding, a technique for magnetic resonance imaging. One advantage of this technique istthat it can be used to efficiently encode edge features of the object being imaged. This has a particular diagnostic application in tracking heart wall thickness during the cardiac cycle, which we present along with some experimental results along this line. We also present an analysis of the signal-to-noise ratios of images formed with this technique, as this is a factor of paramount importance in MRI. The fact that wavelet schemes tend to concentrate energy near edge features makes the result rather different than that found in standard Fourier based approaches. We indicate an exciting potential application of our technique: reducing spectral leakage in phosphorus spectroscopy.     

Preparation of targeted microbubbles: ultrasound contrast agents for molecular imaging

Targeted ultrasound contrast agents can be prepared by attaching targeting ligands to the lipid, protein or polymer shell coating of gas-filled microbubbles. These materials are stable on storage, fully biocompatible and can be administered parenterally. Detection of microbubble contrast agents by ultrasound is very efficient (single particles with picogram mass can be visualized). Covalent or noncovalent binding techniques can be used to attach targeting ligands. Ligand-carrying microbubbles adhere to the respective molecular targets in vitro and in vivo. Several biomechanical methods are available to improve targeting efficacy, such as the use of a flexible tether spacer arm between the ligand and the bubble, and the use of folds on the microbubble shell, that project out, enhancing the contact area and increasing the length of the lever arm.     

急性心肌梗塞的MR灌注成像及延迟扫描：实验研究并与病理对照

目的 探讨首过MR（磁共振）灌注成像和延迟扫描对预测存在梗塞风险的心肌和评价梗塞面积的价值。方法在导管法冠状动脉造影的指导下将凝胶海绵注射入11只比格犬的左前降支（left anterior descending,LAD）的中部阻塞血管,首过法MR灌注成像在LAD阻塞后30min内进行,3d后行MR增强延迟扫描。对心肌切片采用2,3,5,氯化三苯基四氮唑（triphenyltetrazolium chloride,yrc）染色,比较MR延迟扫描和TTC染色切片上心肌梗塞的面积。结果3只犬制作心肌梗塞模型过程中死亡,8只犬存活并完成实验。MR灌注成像30min内即显示阻塞血管供血区低灌注。延迟扫描和TTC染色切片上测量心肌梗塞大小分别为0．281±0．056和0．307±0．070,两者间有相关性（r=0．86,P=0．008）。结论MR灌注成像和延迟扫描可以预测存在梗塞风险的心肌和评价梗塞面积,进而指导临床干预和判断预后。     

MRI弥散加权成像表观扩散系数在低、高级别脑膜瘤鉴别诊断中的应用

目的 探讨常规MRI结合弥散加权成像(DWI)中表观扩散系数(ADC)在低、高级别脑膜瘤的鉴别诊断中的临床应用价值。方法 回顾性分析中国科学技术大学附属第一医院2018年1月-2019年8月68例脑膜瘤患者的临床资料,男29例、女39例,年龄24~78(48.62±10.28)岁。其中WHOⅠ级脑膜瘤52例(低级别组),WHO Ⅱ级12例、WHO Ⅲ级4例(高级别组)。患者术前均行常规MRI结合DWI检查。观察两组患者的MRI征象以及DWI特点;比较两组患者脑膜瘤实质和瘤周水肿部位ADC值以及肿瘤实质与对侧脑白质的相对表观扩散系数(rADC),利用ROC曲线分析最佳rADC值对低、高级别脑膜瘤的诊断效能。结果 两组患者基线资料差异均无统计学意义(P值均＞0.05)。高级别组脑膜瘤边缘不规整、强化不均匀、边缘水肿区、脑膜尾征和囊变、坏死、钙化区等影像学征象发生率明显高于低级别组脑膜瘤,差异均有统计学差异(P值均＜0.05)。52例低级别组脑膜瘤中,有38例DWI、ADC均呈等信号,14例DWI呈稍高信号、ADC呈稍低信号;16例高级别组脑膜瘤实质部分DWI呈高信号、ADC呈低信号,而囊变、出血坏死、钙化区呈高信号。低级别组、高级别组脑膜瘤肿瘤实质部分 ADC值分别为(0.94±0.14)×10^-3、(0.73±0.11)×10^-3 mm²/s,rADC值分别为(1.16±0.18)×10^-3、(0.95±0.14)×10^-3 mm²/s,低级别组脑膜瘤实质部分ADC和rADC值均明显高于高级别组脑膜瘤,差异均有统计学意义(t=5.491、4.277, P值均<0.01);低级别组、高级别组脑膜瘤的瘤周水肿区域ADC分别为(1.82±0.19)×10^-3、(1.88±0.21)×10^-3 mm²/s,rADC值分别为(2.29±0.24)×10^-3、(2.38±0.29)×10^-3 mm²/s,差异均无统计学意义(P值均>0.05);以rADC值诊断低级别组、高级别组脑膜瘤的最佳临界点为1.035×10^-3 mm²/s,其灵敏度为88.5%,特异度为87.5%。结论 常规MRI结合DWI中ADC值的测量对低、高级别脑膜瘤的鉴别诊断具有重要临床应用价值。     

Accurate identification of myocardial viability after myocardial infarction with novel manganese chelate‐based MR imaging

We developed a novel manganese (Mn²⁺) chelate for magnetic resonance imaging (MRI) assessment of myocardial viability in acute and chronic myocardial infarct (MI) models, and compared it with Gadolinium‐based delay enhancement MRI (Gd³⁺‐DEMRI) and histology. MI was induced in 14 rabbits by permanent occlusion of the left circumflex coronary artery. Gd³⁺‐DEMRI and Mn²⁺ chelate‐based delayed enhancement MRI (Mn²⁺ chelate‐DEMRI) were performed at 7 days (acute MI, n = 8) or 8 weeks (chronic MI, n = 6) after surgery with sequential injection of 0.15 mmol/kg Gd³⁺ and Mn²⁺ chelate. The biodistribution of Mn²⁺ in tissues and blood was measured at 1.5 and 24 h. Blood pressure, heart rate (HR), left ventricular (LV) function, and infarct fraction (IF) were analyzed, and IF was compared with the histology. The Mn²⁺ chelate group maintained a stable hemodynamic status during experiment. For acute and chronic MI, all rabbits survived without significant differences in HR or LV function before and after injection of Mn²⁺ chelate or Gd³⁺ (p > 0.05). Mn²⁺ chelate mainly accumulated in the kidney, liver, spleen, and heart at 1.5 h, with low tissue uptake and urine residue at 24 h after injection. In the acute MI group, there was no significant difference in IF between Mn²⁺ chelate‐DEMRI and histology (22.92 ± 2.21% vs. 21.79 ± 2.25%, respectively, p = 0.87), while Gd³⁺‐DEMRI overestimated IF, as compared with histology (24.54 ± 1.73%, p = 0.04). In the chronic MI group, there was no significant difference in IF between the Mn²⁺ chelate‐DEMRI, Gd³⁺‐DEMRI, and histology (29.50 ± 11.39%, 29.95 ± 9.40%, and 29.00 ± 10.44%, respectively, p > 0.05), and all three were well correlated (r = 0.92–0.96, p < 0.01). We conclude that the use of Mn²⁺ chelate‐DEMRI is reliable for MI visualization and identifies acute MI more accurately than Gd³⁺‐DEMRI.     

Course of cerebral lesions in a patient with periarteritis nodosa studied by magnetic resonance imaging

Summary The course is reported of a patient with periarteritis nodosa who initially presented with neurological symptoms. Multiple cerebral lesions were documented by the first magnetic resonance imaging (MRI) investigation. The majority of these had disappeared completely in the follow-up MRI studies. In contrast to neurological improvement the patient eventually died due to multiorgan failure. Postmortem histological examination revealed no pathological findings in the brain except one single necrotic area already known from MRI. Remissions of histological and angiographic alterations in periarteritis nodosa have been described as local healing leading to fibrosis and scarring. Our findings suggest that restitutio ad integrum may occur, at least in cerebral lesions.Abbreviations PAN panarteritis nodosa - MRI magnetic resonance imaging - CT computerized tomography - CNS central nervous system     

Sexual dimorphism and handedness in the human corpus callosum based on magnetic resonance imaging

The corpus callosum (CC) is a major anatomical and functional commissure linking the two cerebral hemispheres. With MR imaging in the sagittal plane, the corpus callosum can be depicted in great detail. Mid-sagittal magnetic resonance images of 80 normal individuals were analyzed to assess whether or not the morphology of the corpus callosum and its parts are related to sex and handedness. The subjects were 40 males (20 right-handers and 20 left-handers) and 40 females (20 right-handers and 20 left-handers). The midsagittal area of the corpus callosum was divided into seven sub-areas using Witelsons method. The most striking morphological changes concerned left-handers, who had larger areas of the anterior body, posterior body and isthmus than right-handers. In addition, right-handed males had larger rostrums and isthmuses than right-handed females. These significantly increased areas were related to handedness in right-handed males. However, left-handed males had larger anterior and posterior bodies than right-handed males. In contrast, there was no significant difference between left-handers and right-handers in females. The areas of the rostrum and posterior body of the corpus callosum increased significantly with sex in males. Moreover, there were no significant age-related changes in the total corpus callosum and sub-areas of the corpus callosum. In conclusion, these anatomical changes in corpus callosum morphology require taking the sexual definition and dominant handedness into consideration.     

星形细胞肿瘤磁敏感成像与动态对比剂MR灌注加权成像的相关性研究

目的：探讨星形细胞肿瘤磁敏感加权成像（ SWI)半量化与动态对比剂增强MR灌注加权成像（ PI)的相关性。方法回顾性分析98例经手术病理证实星形细胞肿瘤患者的术前SWI及PI检查资料。测量SWI中肿瘤内磁敏感低信号区（ ITSHIA)半量化数据,以及PI中肿瘤内实性部分最大相对脑血流量值（ rrCBV瘤内max )和瘤周区最大相对CBV值（ rrCBV瘤周max )。应用Kruskal-Wallis H检验比较不同病理分级星形细胞肿瘤间rrCBV瘤内max与rrCBV瘤周max的差异,比较不同级别肿瘤间灌注热点区与ITSHIA形态的对应情况;应用Spearman相关性检验比较不同级别肿瘤间SWI中各半量化指标与PI中rrCBV瘤内max与rrCBV瘤周max的相关性。结果星形细胞肿瘤rrCBV瘤内max值（ rs =0．662,P<0．01)及rrCBV瘤周max值（rs =0．794,P<0．01)与其分级显著相关。毛细胞型星形细胞瘤rrCBV瘤内max高于Ⅱ级星形细胞瘤,与Ⅲ级肿瘤类似;而 rrCBV瘤周max与Ⅱ级星形细胞瘤差异无统计学意义（ P >0．05),却低于高级别肿瘤。星形细胞肿瘤的ITSHIA半量化指标与rrCBV瘤内max与rrCBV瘤周max值呈显著线性正相关。星形细胞肿瘤内灌注热点区与ITSHIA不完全对应。结论星形细胞肿瘤SWI指标与PI指标密切相关,二者对于术前评估星形细胞肿瘤的病理分级同样具有较高价值。灌注热点区与ITSHIA并不完全相同,可能与二者显示肿瘤内血管生成的机制不同有关。     

酪氨酸酶基因在HEK293细胞表达的MRI评价

目的:以酪氨酸酶基因作为报告基因转染HEK293细胞, 利用其合成大量黑色素而能被MRI检测的特性来反映基因表达的情况, 以探索磁共振成像(MRI)评价体外细胞基因表达的方法。方法:以脂质体将含酪氨酸酶基因完全cDNA的pcDNA3tyr质粒转染到HEK293细胞, 以MRIT₁WI、T₁WI/SPIR、T₂WI序列扫描转染细胞, 观察表达的黑色素的MRI信号。应用Fontana染色检测黑色素的合成, RT-PCR检测酪氨酸酶基因的cDNA片段, 以进一步验证酪氨酸酶基因的转染与表达。结果:(1)pcDNA3tyr质粒转染进入HEK293细胞并在其中表达生成黑色素, 转染5μg、10μg、20μg质粒的10⁶个细胞内生成的黑色素能够被MRI检测到并在MRIT₁WI、T₁WI/SPIR、T₂WI检查呈高信号, MRI信号强度与转染质粒量成正相关。(2)Fontana染色法检测到HEK293细胞内的黑色素颗粒;(3)采用RT-PCR方法检测到转染的HEK293细胞含酪氨酸酶基因的cDNA片段。结论:MRI能够检测到HEK293细胞内由外源基因表达合成的黑色素, 说明影像学与分子生物学技术结合可以评价体外细胞基因表达的情况。     

Combining structural and functional neuroimaging data for studying brain connectivity: a review

Different brain areas are thought to be integrated into large-scale networks to support cognitive function. Recent approaches for investigating structural organization and functional coordination within these networks involve measures of connectivity among brain areas. We review studies combining in vivo structural and functional brain connectivity data, where (a) structural connectivity analysis, mostly based on diffusion tensor imaging is paired with voxel-wise analysis of functional neuroimaging data or (b) the measurement of functional connectivity based on covariance analysis is guided/aided by structural connectivity data. These studies provide insights into the relationships between brain structure and function. Promising trends involve (a) studies where both functional and anatomical connectivity data are collected using high-resolution neuroimaging methods and (b) the development of advanced quantitative models of integration.     

磁共振T2-Mapping成像对呼吸衰竭患者心肌损害的临床应用价值

目的　探讨磁共振T2-Mapping成像对呼吸衰竭患者心肌损害的临床应用价值。 方法　选择2016年8月到2018年12月本院内科诊治的呼吸衰竭患者122例作为研究组，同期无呼吸衰竭病史的78例内科患者作为对照组。所有患者给予超声心动图与磁共振T2-Mapping成像，记录成像参数并进行相关性分析。 结果　衰竭组的DT值高于对照组（P<0.05）；两组E/A与Pulmonary S/D ratio值对比无统计学差异（P>0.05）；两组心磁共振图像质量Ⅲ级与Ⅳ级分别占比80.3%、9.8%和76.9%和12.8%，对比均无统计学差异（P>0.05）；衰竭组短轴位与长轴位的左心室前壁、后壁T2值均大于对照组（P<0.05）；衰竭组患者中，Pearson相关性分析显示短轴位、长轴位的左室前壁、后壁T2值与DT值均呈正相关性（P<0.05）。 结论　磁共振T2-Mapping成像能反映呼吸衰竭患者心肌损害情况，通过定量评估心肌T2值可有效评估左心室心肌功能，对指导临床治疗方案的抉择和预后判断具有重要作用。